The present disclosure relates to a sheet conveying device for conveying a sheet, and an image reading apparatus and an image forming apparatus provided with the same.
Conventionally, an automatic document feeder arranged in an automatic document reading unit of an image forming apparatus is known as a sheet conveying device for conveying a sheet. In such an automatic document feeder, a feeding unit is arranged to face a document tray on which a plurality of documents (document stack) are stacked. The sheet feeding unit includes a pickup roller and a feed roller. When the pickup roller feeds documents, the uppermost document is conveyed to a downstream side in a sheet conveying direction by the feed roller.
If the document stack is forcefully inserted to a position toward which the sheet feeding unit of the automatic document feeder is facing, the plurality of documents are squeezed around the feed roller. As a result, it is blocked that the documents are fed one by one by the feed roller. Conventionally, a stopper is known which projects between a pickup roller and a feed roller to prevent the documents from entering around the feed roller when documents are placed. The stopper is rotatably supported on a cover member of the automatic document feeder. Further, the stopper is fixed at a restricting position to restrict the documents by contact with a fixing member arranged on the cover member.
In the above technique, if a user brings a document stack into collision with an upper part of the cover member to align one end edge of the document stack, vibration is applied to the sheet feeding unit to move the sheet feeding unit. In this case, the stopper is separated from the fixing member and moved from the restricting position, with the result that there has been a problem that the entrance of documents cannot be restricted.
The present disclosure was made in view of the above problem and aims to stably realize a position change and posture keeping of a stopper for restricting the entrance of sheets to a sheet feeding position in a sheet conveying device for conveying a sheet and an image reading apparatus and an image forming apparatus provided with the same.